Mesh objective damage modeling of ductile fracture at visco-plastic continuum response

Abstract

Local-continuum damage models, such as the JC-dynamic failure criterion are often combined with the constitutive JC-model to represent the material behavior during machining. The major drawback is that the failure criterion exhibit a pathological mesh dependence. In literature it has been argued that a viscous regularization of the continuum material model coupled to damage via visco-plasticity may remove the mesh dependence. We present results, based on the objective enhanced element removal model derived from previous contribution, form a mesh dependence study using a extended formulation of the constitutive JC-model covering visco-plasticity. The results show that, excluding the mesh objective enhancement the pathological mesh dependence still exist if the visco-plastic formulation is used. If the mesh objective enhancement is used a relatively good convergence is obtained for a set of mesh sizes for the damage model.